Great music and crucial artists deserve proper introductions to their performance. MCs 'officiate', i.e. make the show 'official', making sure the show runs in a smooth and timely manner. A good MC such as Jr. Francis can really build the energy of a set and pump up the crowd. A not so good MC can conversely ramble onstage, be too wordy or understated, and drain a show of its impact. It's an important position in the presentation of an event like SNWMF.

Is there really a need for DJs blathering on and on between sets?
Just let music play between sets.

Brevity is the soul of wit/ tediousness has been some of the MCs from years past---

I think Shakespeare said that. There ARE announcements that need to be said. Said announcements should be delivered literally live & direct --- & quickly. Otherwise, play the music selector until it's Star Time; then a proper fast intro!